Most of the subsea well casing suspension systems currently employed in, or otherwise known to, the petroleum industry comprise a stacked downhole nesting of casing hangers, i.e., each progressively smaller hanger is stacked on, and thus supported by, the top of the previously installed hanger, whereby the total hang load of all the casing strings and their hangers plus the operating pressures in the well to which said strings and hangers are subjected is transferred to the wellhead at a single location near its base. There is a growing need in this industry for casing suspension systems capable of supporting hang loads and operating pressures considerably in excess of those for which the foregoing stacked systems were designed, and lately some higher performance designs have been proposed. However, most of these later designs result in placing all, or almost all, casing hang load and pressure load in a load path connection to a compressive load-carrying, hanger-bearing shoulder at the wellhead base. This stacked arrangement limits the hanger load carrying capability of the entire system, especially where it is exposed to a hydrogen sulfide environment which requires use of lower strength steels.